1. Field of the Invention
The invention relates to a vehicle light distribution control device and a vehicle light distribution control method.
2. Description of Related Art
There is known an existing in-vehicle lamp control device that, when an abnormality of any one of a low beam head lamp and a high beam head lamp has been detected, executes fail-safe process in which the other one of the low beam head lamp and the high beam head lamp, which is in a normal condition, is turned on instead of the one of the head lamps, which is in an abnormal condition (for example, see Japanese Patent Application Publication No. 2000-233679 A (JP 2000-233679 A)).
In addition, there is known variable high beam light distribution control in which, in order not to cause a driver, or the like, of a vehicle ahead, such as a leading vehicle and an oncoming vehicle, to experience glare, the light distribution of illumination light for illuminating an area ahead of a vehicle is controlled on the basis of a vehicle ahead, detected by a camera (for example, see Japanese Patent Application Publication No. 2011-005992 (JP 2011-005992 A) and Japanese Patent Application Publication No. 2011-063070 (JP 2011-063070 A)).
However, in a vehicle light distribution control device that executes the above described variable high beam light distribution control, when there occurs a failure during variable high beam light distribution control, it is required to stop high beam irradiation and change the light distribution into low beam irradiation. At this time, when high beam irradiation is stopped and the light distribution is changed into low beam irradiation immediately after there occurs a failure, there is an inconvenience that the visibility of a distant area steeply decreases. This inconvenience not only occurs in variable high beam light distribution control but also can occur in other light distribution control, such as automatic high beam control.